A apparatus for making spun-filament fleece for making a spun-filament fleece is known comprising a spinning nozzle system or spinneret, a cooling shaft for the continuous spun filament, a stretching gap (e.g. a venturi passage in which air flow is accelerated), a diffuser shaft, a continuously moving fleece receiving conveyor and a device for feeding process air and for drawing outflowing air through the fleece receiving conveyor.
The cooling shaft has a shaft wall provided with a plurality of air orifices and process air required for cooling can be introduced through the air orifices to provide an air flow. The air flow is at least partially drawn through the fleece receiving conveyor.
In the known apparatus for making a spun-filament fleece or mat the process parameters such as the flow rates of thermoplastic material and process air the transport speed of the fleece receiving conveyor and the geometric parameters of the apparatus for making a spun-filament fleece are set up in practice so that the spun-filament fleece has a thickness, or surface weight (area weight), which is as uniform and exact as possible. However it is not possible with the features of the known process and/or in the apparatus for making spun-filament fleece to successfully correct or even regulate the thickness variations of the spun-filament fleece or the deviations from a uniform thickness.